There are several patents which address inhibiting unauthorized calls from standard telephone stations.
One of these, Smith, U.S. Pat. No. 4,612,419, entitled "Toll Restriction Circuit for an Electronic Telephone Station", describes a means controlling toll calls only, and is employed within the telephone station itself. It looks for a "0" and "1" in the first dialed digit. The subscriber can lock and unlock the device via keypad entry of an enabling or disabling code.
Another device is disclosed in Murray, U.S. Pat. No. 4,358,640, entitled "Telephone Security Device," and describes a circuit which claims to have means to allow or disallow toll calls on entry of a programmable code stored in an EAROM (electrical alterable read-only memory). This device is claimed as an integral part of a telephone station or connected to the same. The device claims use of a three digit authorization code to set a mode register means which is detected and acted on by the circuitry. The mode register means restricts the telephone station in question to either of three states; namely normal, local, or restricted. The invention claims use with pulsed dial operation only.
Yet another patent is described is Kossor, U.S. Pat. No. 4,683,583, entitled "Method and Apparatus for Controlling Telephone Line Access." This invention describes a means of preventing unauthorized calls from being placed from conventional or cordless type receivers. As in the previously described patents, this patent depends on use of code sequences to enable or disable uses of a particular telephone device. This invention describes limiting all calls or allowing all calls via the described code, or via a mechanical key device.
Still another approach is claimed in Sharvit, U.S. Pat. No. 4,346,264, entitled "Telephone Call Restriction Apparatus." In this invention, Sharvit refers to means to inhibit pulse dial type calls from being routed through a PABX (Private Access Branch Exchange) in two different modes. In one mode, unless an access code is received as the first three digits, the remainder of the number is prohibited. In the second mode, a means is provided to inhibit all numbers beginning with certain numbers such as `1` and `0`, or specific three digit codes for local exchanges which one may wish to prohibit. Sharvits also teaches a means of putting this in a standard telephone circuit or PABX. The intent of this invention is to allow control of PABX services to specific exchanges or groups of exchanges, and to limit toll calls to specific authorized individuals, when used in conventional pulse dial applications.
Sharvit also teaches a means of loading the line so as to inhibit outgoing dial pulses to a central office, yet still allowing his described circuit to detect and count dial pulses and operate his circuit as he describes.
In another patent of the same title, Sharvit U.S. Pat. No. 4,314,108, shows the above means of restricting calls, but necessitates clearing the line to the central office, and obtaining another dial tone before allowing an authorized call to go through.
In all the above-discussed prior art, means to detect, decode, and react to specific numbers is shown. In addition, the art shown describes many ways to restrict calls by interrupting the call process. The prior art show a means of either setting an apparatus to screen or partially screen toll calls, or require an access code preceding the desired dialed number. In all cases, all of the devices allow non-prohibited originating telephone dial signs to be directly passed through to the central office without modification after a logical means has determined if a call is prohibited or not.
An inherent difficulty and deficiency of the prior art is that all these restriction means must use the first digit or first few digits to provide access or inhibit a dialed number. It is neither obvious from any of the prior art how to restrict a call based on a number of numbers contained at any location within a sequence of numbers without interpreting it as a nonprohibited call, nor is it discussed as a possibility, nor until very recently, has the need to do so existed. The prior art does not disclose a means of intercepting, diverting, and retaining an entire number or any part or parts of a number until logical means detects and allows an authorized call to go through, or a repeating means completes the call by dialing any or all of the retained digits. None of the existing art show or hint at a means of allowing part of a number to be dialed to the central office and then restricting the rest of the number unless the number(s) is/are the first one(s) dialed. Such art as shown does not teach us how to construct a machine which can retain a dialed number and parse it against any number of prohibited combinations of numbers or parts of numbers, and redial it if required.
The prior art also does not show a system which can be used to provide a limited list of numbers or partial numbers which can be successfully dialed out.
It is the object of this invention to overcome these limitations, and provide a universal means of prohibiting unauthorized numbers from being dialed or generated from any phone PABX, central office, computer, or communications means, which would allow an unauthorized connection or information passage between two devices which use DTMF (Dual Tone Multifrequency), dial pulses, or other sequential number transmission means to establish communications, either verbal or non-verbal.
Since the above patents were granted, a demand has developed to control telephone devices in a more universal manner. Such developments are typified, for example, by the so-called in-bound telemarketing groups. Such groups advertise on national media and have the undesirable side effect of enticing minors and irresponsible individuals to call their numbers. Groups are then paid via telephone company billing for minute total toll charges.
As of this filing, some telephone companies are offering screening of select area groups such as 1-976-xxx-xxxx or 1-900-xxx-xxxx numbers, but they are charging in some instances, and the selection is fixed. No options are available for screening other than this type call, with the exception of screening all long distance toll calls. The telemarketing groups by their nature will devise more and varied numbers to confound any effort by any simple scheme such as the telephone company has currently employed.
Additionally, there are simply many cases where it would be desirable to be able to reliably and efficiently restrict any desired telephone number, or class or telephone number. Analogously, there are situations where it is desirable to ensure that only certain numbers or numbers with certain partial sequences, are allowed to be successfully completed. There are various desirable reasons for such a system, but, at present, this need has not been recognized and no satisfactory system has been created to meet this need.
The invention herein described overcomes inherent limitations of the other patents described and existing prior art in dealing with the above problems by providing a universally usable means for screening all outgoing calls of an unwanted or restricted nature, regardless of the nature or length of the number, or regardless of whether the call is a local or long distance toll charge. By being universally programmable, the herein described invention improves over or solves the deficiencies and problems in the art, and provides novel and unique advantages over the prior art.
Additionally, the present invention can be added to any single phone jack without effecting any other extensions on that line.